1. Field of the Invention
The present invention relates generally to a digital broadcasting system, and more particularly to a method and a digital broadcasting system for transmitting and receiving an Electronic Service Guide (ESG).
2. Description of the Related Art
The term “digital broadcasting” generally refers to a broadcasting service which provides users with higher quality images, sound and other services than conventional analog broadcasting. The digital broadcasting includes, for example, Digital Multimedia Broadcasting (DMB), Digital Audio Broadcasting (DAB), Digital Video Broadcasting (DVB) and Digital Video Broadcasting-Handheld (DVB-H).
Particularly, the DVB system is a European digital broadcasting technology that refers to a transmission standard for supporting a mobile/portable digital multimedia service as well as the existing digital broadcasting.
The DVB system can multiplex Moving Picture Experts Group 2 Transport Stream (MPEG2 TS)-based broadcast data, and transmit an Internet Protocol (IP)-based data stream simultaneously with the multiplexed MPEG2 TS)-based broadcast data. Also, the DVB system can multiplex several services, and transmit the multiplexed services in one IP stream. In the DVB system as described above, a broadcast receiving terminal receives data transmitted in an IP stream and then demultiplexes the received data into separate services. Then, the broadcast receiving terminal demodulates the demultiplexed services, and outputs the demodulated services to a screen. Accordingly, a user can conveniently use a broadcasting service.
Meanwhile, when viewing a broadcast, the user needs information regarding, for example, the types of services that are provided by the DVB system and the contents that are included in each of the services. Accordingly, the conventional DVB system includes an ESG for providing information on each service. The ESG data includes such information as the time on a particular service, content related to the particular service, and information for receiving the related contents and for purchasing the related contents.
The DVB system transmits ESG data in either a single IP stream or in one or more IP streams when the capacity of the ESG data is large. Herein, using a single IP stream to transmit the ESG data is referred to as a “single stream mode,” whereas using one or more IP streams to transmit the ESG data is referred to as a “multi-stream mode.”
FIG. 1 illustrates a conventional process of transmitting ESG data in a multi-stream mode.
In FIG. 1, the broadcast receiving terminal checks an IP address of an ESG Bootstrap File Delivery over Unidrectional Transport Protocol (FLUTE) session from Program Specific Information/Service Information (PSI/SI) corresponding to a control signal channel in the DVB system.
The ESG Bootstrap FLUTE session is used to transmit information such as basic information of the ESG data on a provider of the ESG data, and a list of the ESG data provided by the relevant provider. The information as described above is transmitted from each of an ESG provider information (i.e. an ESG Provider Discovery Descriptor) field and an ESG access information (i.e. an ESG Access Descriptor) field. Particularly, an IP address of an ESG Announcement Carousel FLUTE session of each ESG data is transmitted from the ESG access information field.
Each piece of ESG data includes one ESG Announcement Carousel FLUTE session, which is used to provide brief information on the transmission and a configuration of the ESG data. Specifically, an ESG Init Message field in the ESG Announcement Carousel FLUTE session is used to transmit a compression method of an ESG container and parameters related to the compression method. Also, a Partition Declaration field in the ESG Announcement Carousel FLUTE session is used to transmit parameters that are respectively assigned partitioning criteria, such as a time and a service IDentifier (ID).
In addition, an Index List field, an Index Structure field, and a Multi Field Sub Index field are used to transmit structure information of the ESG data which is divided into several pieces of data, which are then transmitted. Namely, the fields are used to transmit information on which IP streams with a piece of ESG data are divided and are then transmitted, a container list of the multiple pieces of ESG data transmitted in the respective IP streams, and a list on ESG fragments included in each of the containers. Accordingly, by using the information as described above, the broadcast receiving terminal can recognize how the relevant ESG data is divided into multiple pieces of data which are then transmitted, without directly connecting to a session in which actual ESG data is transmitted.
The broadcast receiving terminal can receive an IP address, from which the actual ESG data is transmitted, from the Partition Declaration field, and can connect to a relevant ESG FLUTE session. At this time, the broadcast receiving terminal receives all ESG Fragment Containers in which the actual ESG data is included, and decodes all of the received ESG Fragment Containers, thereby completing one ESG data.
Meanwhile, in the single stream mode, the ESG Announcement Carousel FLUTE session does not exist differently from the case of the multi-stream mode as described above. Accordingly, in the single stream mode, an ESG Init Container is included in an ESG Single Stream FLUTE session in which the actual ESG data is transmitted, and the ESG Single Stream FLUTE session with the ESG Init Container is then transmitted. Also, in this case, the ESG Init Container does not include a Partition Declaration field differently from the case of the multi-stream mode.
The conventional ESG data is defined as a mechanism transmitted through a broadcasting network. Along with a general service, the ESG data can be provided through the broadcasting network and a communication network, but there is no defined signaling scheme for reporting if there is an update of all or part of the ESG data transmitted through the communication network. Accordingly, so that the broadcast receiving terminal may more conveniently receive the ESG data transmitted through the communication network in a point-to-point scheme, there is a need for a mechanism transmitting information that can be more conveniently received by the broadcast receiving terminal.